Steam boiler



Sept. 20, 1927.

C. w. OBERT STEAM BoILEa Filed Aug. l. 1924 2 Sheets-Sheet 1 BY @f2/21M.

MINIMUM l'ihlll t H QN 4* ATroRNEY. A

Sept. zo, 1927. 1,642,692

C. W. OBERT STEAM BOILER Filed Aug. l. 1924 2 Sheets-Sheet 2 Patented Sept. 20, 1927.

UNITED sra @esA serum OFFICE.

STEAM norman.

Application filed August 1, 1924. Serial No; 729,431.

This invention relates to steam boilers and has for one of its objects to provide an improved arrangement ofthe water tubes'and lire'tubes with a certain circulation of the productsI of combustion whereby lthe heat units generated from the fuel consumed are utilized to a maximum rdegree in the conversion of the water into steam.

ln one embodiment of my present improvements I provide water-circulating tubes in the lirebox, extending longitudinally over the fire from the lower portion of the rear water leg, forward to the upperportion of the front water leg, whichin connection with the main boiler heating surface comwv prising the usual plurality of longitudinal fire tubes extending longitudinallyabove the crown sheet from the rear head to the fronthead of the boiler, combine in a novelA and improved form botl lire-tube boiler characteristics and water tube boiler characteristics. This combination, particularly on account of the direct and uninterrupted exposure .of the furnace water tubes tothe radiant heat of 'the lire, :causes a great rapidity of water circulation in these water tubes from the lower portion of the rear water leg wherel the coolest water in the boiler normally settles, up and into the upper portionof the front water leg, and gives a new arrangement of water circulation in the entire boiler interior, whereby the con tents of the fire-tube boiler portion above the crown sheet is kept constantly stirred and moving from the front to the rear portions, in counter-flow to the flow of the gases from the .point-s of coolesty gases'to the hottest gases. lVith this circulation arrangement, no stagnantwater pockets can exist in any portion of the boiler and every part of the fire tubes above the crown sheetis thoroughly scoured by the water circulating rapidly out of the 4furnace water tub-es. This obviously improves the rate and i ncreases the amount of heat transfer of the boiler, vand .tends toward increased efficiency and capacity when in operation. n Yi/'bile either of thesetwojprincipal elements have heretofore been'extensively used separately in boiler Construction, their combination in thisfarrangemellt Provides a boiler of ncreasedcaplacity and 'e'cency and constitutes an important practical improvement in ,the art. Suche/combination of parts produces also anew co-oper-atfion thereof anda new result.

Another 'import-ant feature of this new and improved design of boiler is the design of furnace which occupies the entire length of the tire box from front to rear water leg, with. crown sheet the entire length. and the application of the grate into one end thereof only, so as to constitute notmore than from to 75 per cent of the furnace area, which affords a new and heretofore unused proportion of furnace volume to gra-te area. This is claimed as an important improvement in furnace construction, because, the long lgas and flame t-rav'el'in the furnace in sures a full and complet-ecombustion of the fuel and gases before they reach the end furnace plates or the tubes, and before they are cooled thereby so asto cause smoke.

'In addition, the water circulation tubes in the furnace are especially shaped so as to support a fire brickarch over the lire, for use with bituminouscoal, which in combination with the above juxtaposition of ,lire tubes and water tubes constitutes a practical improvement in the art. The fire brick arch which is exposed directlyA to the fire,

becomes highly heated and incandescent therefrom and by virtue of this retained heat which is reflected back to the fuel bed as the gases flow in increased length of travel, rapidly kindles fresh fuel, when applied, and brings about complete combustion and freedom from smoke. i

Therefore, the elements ofv my invention comprise the counterliow actions of combus-A tion gases and water to be heated, the combination of furnace water tubes and fire tubes above a longitudinally extending crown sheet, a fire box of full length of boil-er and providing ample combustion space, and in event of use of bituminous coal, a lire brick arch that increases the length of gas travel and insures 'complete ness of combustion. ,f tv is a further general object ofthe invention to provide a steam"boiler of the above character which isa very economical construction' and the several novel features thereof are susceptible of use in connection with` stationary, "marine or locomotive boilers. y

' With the above Aand other objects in View, the invention consists inthe improved steam Fig. 2;

Fig. 2 is a transverse section taken on the line 2 2 of Fig. 1.

Referring' to the drawings, the outer body shell 5 of the boiler and the inner shell 6 thereof are arranged in spaced relation to each other and in conjunction therewith there are provided front and' rear water legs 7 and 8 respectively, communicating with the side water 'legs 9. The inner and outer shells 5 and 6 are connected at their forward ends to provide the fuel feed opening 10, said shells I thereto.

being also connected at their rear ends by the tubular member 11 which provides a passage opening into the rear chamber 12.

rllhe lire-box 13 of the boiler is provided with the usual grate 14 of any preferred construction. which supportstlie fuel bed. At the rear side of the .fire-box a transverse bridge wall 15 is arranged and provides an intermediate support for a series of longi-l tudinally extending water tubes 16. rl`he rear ends of these water tubes communicate with the lower end of the rear waterleg 8, said tubes extending forwardly and upwardly at a gradual inclination and being connected at their forward ends to the upper end. of the front water leg 7.

Above the crown sheet 17 of the inner shell 6 a plurality of parallel fire tubes 18 are arranged and communicate'at their rear ends with the chamber 12 and at their forward ends with the outlet flow 19 which is in communication with the stack leading to the atmosphere.

The top wall of the outer shell 5 of the boiler is provided with a suitable opening 20. for the connection of a steam outlet pipe 20al In the operation-of the boiler as above described, it will be understood that the coldest water will seek the lowest level in the water legs. These water legs, the tube 16 and the space above the crown sheet 17 to a point above the uppermost fire tubes 18 is completely filled with water, and as the water in the tube 16 extending over the fire-box 13 becomes highly heated, it flows upwardly through said tubes, the relatively cold water entering the rear ends of the tubes from the water leg 8. The hot water is, therefore, continually delivered into the upper end of the front water leg 7. The fla-me and products of combustion, after impinging upon the Water tubes 16 pass rearwardly through the tube 11 into the chamber 12 and into the rearpends of the fire tubes 18 as indicated by the arrows in Fig. 1 of the drawings. It will, therefore, be evident that the relatively high heat of the flame and products of combustion will also be radiated through the wall of the tube 11 and the rear ends of t-he re tubes and such heat absorbed by the relatively cool water passing downwardly around said tubes into the rear water leg 8. After the products of combustion are drawn forwardly through the fire tubes 18, the temperature thereof gradually decreases by the absorption of heat by the walls of said tubes and transmission thereof to the water surrounding said firer tubes so that when the products of'combusvtion reach the forward ends of said tubes and pass into the outlet 19 they will be at a comparatively low temperature, and at this point substantially no heat would be given up by the gases to the water, since the water at this point delivered from the upper forward ends of the tubes 16 is at its highest temperature. The distinction between my present improvements and the ordinary steam boiler is thus clearly evident. ln the 'latter the products of combustion pass from the boiler furnace to the outlet flow at the point where the water is of a relatively low temperature, and only the initial heat of the products of combustion is utilized to its fullest extent. In the arrangement above described, it will be seen that the coldest water is subjected to the highest heat of the llame and products 0f combustion so that the water will be more quickly heated and to a relative'ly higher'temperature than in the present type of furnace with the same fuel consumption. It will also be noted that the flow of the gases and water counter each other. Also, the eliiciency of the boiler is materially increased by arranging the tire tubes- 18 directly above the crown sheet 17. Thus heat will be radiated from the crown sheet and absorbed by the water immediately above the same and surrounding the lire tubes 18 so that water above the crown sheet will at all times be at aV substantially uni-- form high temperature and will not have any appreciable cooling effect upon the tire tubes.

The water circulating tubes 16 in the furnace extend longitudinally over the lire from the lower` portion of rear water leg 8, forward to the upper portion of the front water leg 7. There is, therefore, a great rapidity of water circulation in these water tubes from the lower portion of the rear water leg 8, where the coolest water normally settles, up and into the upper portion of the front water leg 7. A novel circulation is thereby produced, in that, among other things, the contents of the boiler above the crown sheet is kept constantly stirred and moving from the front to the rear portion, in counterflow to the flow of the gases.

The boiler 5 itself, occupies the entire length of the lire box from the front `to the f rear water leg, with the crown sheet 17 the entire length therebetween. The grate occupies only one end thereof, not more than to per cent of thefurnace area. The long travel of the fuel and gases insures a full and complete combustion of the fuel and gases before they reach the end furnace plates, or the tubes, and before they are cooled .and develop smoke.

The tubes 16 are shaped by being bent in a curve, as shown in Fig. l, and preferably so as to support a fire brick arch 30 over the fire, especially adapted for bituminous coal.y

This arch becomes highly heated andincandescent, and its retained heat is reflected back to the fuel bed, and rapidly kindles fresh fuel.

From the foregoing description considered in connection with the accompanyingdrawings, the construction and manner of opera-- resorting to all such'legitimate changes in the-form, proportion and relative arrangement of the several parts as maybe fairly vembodied with the spiritfand scope yof the l invention as claimed.

What I claim is: f A steam boiler comprising: a tubular boiler proper; a front water leg and a rear water leg arranged at and substantially lush with the front end respectively with the rear end of the tubular boiler; a crown sheeton the'tubular boiler; a plurality of compara tively narrowv tubes for the combustion gas extending through the tubular boiler above the crown sheet; a tire box below the front end of the crown sheet; a combustion chamber below the other end of the crown sheet; av gas-reversing box extendingl outside of the rear end of the tubular boilerl and commu nicating with the beforesaid gas tubes; a'

passage through the rear water leg, connecting the combustion chamber with the gas yreversing box; a gas collecting chamber at the front or exit end ofthe gastubes at the outside of the tubular boiler; a single row of spaced comparatively large water circu-l lating tubes, connecting the lowest part of the rear water leg with the upper part of the front water leg and passing through both'the fire box and the combustion chamber; a separating wall between the fire box and the combustion chamber extending from the ground up to the row of water circulating tubes; a lirebrick arch extending from the separating wall along the upper side of the water circulating tubes upwardly for a limited length, adapted to force the flames vof the fire box against the uppermost partr of the water circulating tubes and to reflect some heat back to the fuel on the vfurnace grate.

In testimony that I claim the foregoing as v my invention, I have signed my name hereto.

oAsiN w. oBERr. 

